package org.example;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: ${USER}
 * Date: ${YEAR}-${MONTH}-${DAY}
 * Time: ${TIME}
 */
import java.util.ArrayList;
import java.util.Scanner;


import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public ArrayList<Integer> intersection (ArrayList<Integer> nums1, ArrayList<Integer> nums2) {
        // write code here
        ArrayList<Integer> list = new ArrayList<>();
        for (int x : nums1) {
            if (nums2.contains(x) && !list.contains(x)) list.add(x);
        }
        return list;
    }
    public static void main1(String[] args) {
        Scanner in = new Scanner(System.in);
        int l = in.nextInt();
        int r = in.nextInt();
        int count = 0;
        for(int i = l; i <= r; i++) {
            int val = i;
            while(val != 0) {
                int cur = val % 10;
                if(cur == 2) count++;
                val /= 10;
            }
        }
        System.out.print(count);
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine();
        StringBuilder sb = new StringBuilder(str);
        int len = sb.length();
        int i = 0;
        while (i < len - 1) {
            int x = i;
            if (sb.charAt(i) == sb.charAt(i + 1)) {
                while (x < len - 1 && sb.charAt(x) == sb.charAt(x + 1)) {
                    x++;
                }
                if ((x-i+1) % 2 != 0) x--;
                sb.delete(i, x + 1);
                if (i != 0) i--;
            }else {
                i++;
            }
            len = sb.length();
        }
        if(sb.length() == 0) {
            System.out.println(0);
            return;
        }
        System.out.println(sb.toString());
    }
}